Many thanks for your input, Fraser. It's much appreciated. I remain unclear about this, so please let me try again. Please let me know what I've got wrong here...
Early version (pre-2013, hackable to E60 resolution/menus)
Later version (post-2013, also hackable to E60 resolution/menus)
*ALL* vintages of E30 & E40 can be hacked to E60 resolution/menus, but post-2013 versions will never have the service menus.
'BX' notation has added features for building surveys and a limited temp range. BX features can be unlocked and added to any E30/E40. Existence or absence of 'BX' in the model number does not affect ability to be unlocked.
In other words, *ALL* vintages of E30, E30bx, E40, and E40bx can be hacked to E60 resolution/menus, but post-2013 versions will never have the service menus.
Am I getting closer? And thank you again.